Sanofi will meet with the FDA within two months and decide whether to file an application for the controversial Dengvaxia afterward. (Sanofi/Vincent Moncorgé)

The mess in the Philippines over Sanofi's Dengvaxia is still evolving, but the vaccine maker has shown unyielding faith in its safety and efficacy and will soon decide whether to file for approval in the U.S.

David Loew, head of Sanofi Pasteur, told Reuters that the company would meet with the FDA within two months and decide whether to file an application for the controversial dengue vaccine afterward.

Sanofi had previously been in conversations with the FDA, company spokesperson Jack Cox told FiercePharma. The agency participated in the WHO/Dengue Vaccine Initiative regulatory meeting held in Geneva in June 2015 to provide technical review support for the dengue vaccine dossier to the national regulatory bodies from Mexico, the Philippines, Brazil and other countries, and has been kept regularly updated on the long-term clinical data on the vaccine, according to Cox.

While dengue rarely occurs in the continental U.S., it is endemic in Puerto Rico, as well as in Latin America and Southeast Asia, and could pose a threat to people traveling to those regions, according to the CDC. An FDA approval also would go a long way to easing concerns elsewhere about the safety of the vaccine.

The dengue vaccine is at the center of an uproar in the Philippines, the first country to have introduced it in a mass immunization program. A warning issued by Sanofi in November of the shot’s potential harm to dengue-naïve people triggered a chain reaction, leading to the Philippine government’s decision to suspend its marketing approval and, most recently, announce it will sue the French drugmaker to recover all of its funding on the shot.

Some experts in the Philippines have suggested the drugmaker ignored early warnings, while lawmakers have launched probes into whether there were any wrongdoings between Sanofi and the former administration in getting the vaccine on the market in the first place.

Sanofi has agreed to refund $23 million to the government for unused vaccine but has twice rejected the Philippine Department of Health’s request for a refund for used Dengvaxia, saying doing so would imply that the vaccine is ineffective. It pointed out that no deaths have been scientifically linked to the vaccine, and insisted it complied with all regulations around Dengvaxia.

“You need to ask yourself: What was done with the information that was available at the time? Looking back, I would say no, we would not have done anything differently,” Loew said during an interview with Reuters.

A recent examination of documents filed in Singapore found Sanofi had informed regulators there of the vaccine’s potential risks in 2016, but Thomas Triomphe, Sanofi Pasteur’s Asia-Pacific head, said the company didn’t have definitive knowledge until the 2017 revelation that the drug reaction could be severe in those who have never been exposed to the disease, according to the Inquirer.

Following the warning, the WHO has adjusted its position on the use of Dengvaxia to be limited to “individuals with a documented past dengue infection, either by a diagnostic test or by a documented medical history of past dengue illness.” The agency previously suggested Dengvaxia be used where dengue is highly endemic.

An older version of the Reuters story said Loew said Sanofi was holding talks with partners and universities to design a test to identify the right recipients before vaccination, but Cox said it is the regulatory body that will decide on how to address the issue of screening for serostatus prior to vaccination.

Dengvaxia has been approved in 19 countries, and is being evaluated by the European Medicines Agency's Committee for Medicinal Products for Human Use.

Editor's Note: This story has been updated with response from Sanofi spokesperson Jack Cox, including the corrected timeline of a potential filing to the FDA.